Sensitized silver halide emulsions with holopolar dyes containing a dilactone ring



United States Patent Office 3,440,052

Patented Apr. 22, 1969 gen, acyl such as acetyl, alkoxy such as acetoxy, etc. 3,440,052 Particularly good results are obtained with dyes derived SENSITIZED SILVER HALIDE EMULSIO S W from compounds corresponding to Formula I wherein ggg g DYES CONTAININGADILACTONE R and R each represent a methyl group. Such compounds have been referred to in the literature as Mel- Donaid W. Heseltme, Rochester, N.Y., assignor to East 5 dnims lactone which i s 2,2-dLmethyl-4,6-d1keto-1,3-d1ox 33 gg g g Rochester a corporanon ane."Meldrums lactone may be prepared by heating malo- N Drawing. Filed June 1 19 5 Ser. No. 4 3 024 nic' acid With acetone in acetic anhydride solution. This n 03 1 10 compound was originally synthesized by Meldrum in US. Cl. 96-105 3 Claims 10 1908, although the wrong structure was assigned to the compound at that time. The proper structure was reported for Meldrums lactone by Davidson and Bernhard; I. Am. Chem. Soc. 70, p. 3426, 1948. The latter ABSTRACT OF THE DISCLOSURE reference shows preparation of compounds of Formula Photographic Silver halide emulsions are Spectrauy Serb II wherein R and R" are various substituents other than sitized with a holopolar dye containing a dilactone ring. methyl- In one embodiment of this invention, dyes are provided which comprise two heterocyclic nuclei, at least one of'said nuclei being a substituent containing a dilac- This invention relates to polymethine dyes, and to tone gintermediates useful in synthesizing polymethine dyes. Preferably, the {lilactone Ting Containing Substitlleflt as Various polymethine dyes have been prepared from one of the followlng formulas:

cyclic a,a'-diketomethylene compounds, such as 1,3-in- 0 danedione, 1,3-diethylbarbituric acid and 1,3-cyclobutane- IL R,

dione. This invention provides a new class of dyes having at least one methine linkage joining two cyclic nuclei, one

of said nuclei featuring a dilactone ring. The invention 0-0 R" also provides a highly useful dye intermediate containing a dilactone ring substituent. g

One object of this invention is to provide an improved method of making intermediates which are useful in the 0-0 R5 synthesis of polymethine dyes. Another object of this invention is to provide novel intermediates useful in preparing polymethine dyes. Still another object of this in- H vention is to provide new polymethine dyes. A further 0 object of this invention is to provide a new class of polywherein and have the meaning given above, and methine dyes which are useful as optical sensitizers for Y TePTeeI1tS y g P an anion Of a negative photographic silver halide emulsions. Another object of q j Internally satlsfied m P dye molecule; y this invention is to provide novel polymethine dyes which 40 Y are Partlcularly useful accordaflce h 0111' are useful as filter dyes, and photographic silver halide .ll'lVBIlilOIl are represented by the following formulas: emulsion layers containing such novel filter dyes. Other (11) 0 objects of this invention will be apparent from the fol- --Z L- lowing disclosure and the appended claims. 1 I

In accordance with this invention, dyes and dye inter- 5 ll wherein R and R each are selected from the group consisting of alkyl substituents of 1 to 12 carbon atoms,

such as methyl, ethyl, propyl, isobutyl, amyl, octyl and 0-0 B dodecyl, and cycloalkyl nuclei containing from 4 to 6 =CH G carbon atoms, such as cyclobutyl, cyclopentyl and cyclo- R3 R C hexyl. The alkyl substituents and the cycloalkyl nuclei may contain various substituents, such as hydroxyl, halo- In the above formula, R, R R and R each represents a hydrocarbon alkyl substitutent of from 1-2 carbon atoms or substituted alkyl e.g., methyl, ethyl, n propyl, isopropyl, n-butyl, isobutyl, sec. butyl, n-amyl, decyl, dodecyl, B-hydroxyethyl, 'yhydroxypropyl, B-methoxyethyl, ethoxyethyl, allyl, benzyl, fi-phenylethyl, fl-oarboxyethyl, carboxymethyl, -carboxypropyl, sulfopropyl, sulfoalkoxyalkyl, fl-acetoxyethyl, 'y-acetoxypropyl, carbomethoxymethyl, fl-carbethoxyethyl, etc., or an aralkyl or aryl substituent such as phenyl, 'por m-tolyl; R and R each represents a hydrogen atom, methyl, ethyl or the phenyl nucleus; R and -R" have the meaning given above; R and R"" each represent the same substitutents as R' and R"; n and q each represents a positive integer of 1 or 2; Q represents an arylene substituent, such as a phenylene nucleus or a naphthylene nucleus; d represents an integer of from 1 to 4; x and In each represents a positive integer of from 1 to 2; and, Z and Z each represents the nonmetallic atoms necessary to complete a heterocyclic nucleus containing from 5 to 6 atoms in the heterocyclic ring, such as those selected from the group consisting of those of the thiazole series (e.g., thiazole, 4-methylthiazole, S-methylthiazole, 4-phenylthiazole, S-phenylthiazole, 4,5 dimethylthiazole, 4,5-diphenylthiazole, 4- (2-thienyl)thiazole, etc.), those of the benzothiazole series (e.g., benzothiazole, 4-chlorobenzothiazole, S-chlorobenzothiazole, 6-chlorobenzothiazole, 7- chlorobenzothiazole, 4-methylbenzothiazole, S-methylbenzothiazole, 6-methylbenzothiazole, S-bromobenzothiazole, 6-bromobenzothiazole, 4-phenylbenzothiazole, S-phenylbenzothiazole, 4-methoxybenzothiazole, S-methoxybenzothiazole, 6 methoxybenzothiazole, 5 -iodobenzothiazole, 6-iodobenzothiazole, 4-ethoxybenzothiazole, S-ethoxybenzothiazole, tetrahydrobenzothiazole, 5, 6-dimethoxybenzothiazole, 5,6 dioxymethylenebenzothiazole, S-hydroxybenzothiazole, 6hydroxybenziothiazole, etc.), those of the naphthothiazole series (e.g., anaphthothiazole, fl-naphthothiazole, S-methoxy-fl-naphthot'hiazole, 5-ethoxy-B-naphthothiazole, 7-methoxy-anaphthothiazole, 8-methoxy-a-naphthothiazole, etc.), those of the thianaphtheno-7',6',4,5-thiazole series (e.g., 4-methoxythiarraphtheno-7,6',4,'5-thiazole, etc.), those of the oxazole series (e.g., 4-methyloxazole, S-methyloxazole, 4-phenyloxazole, 4,5-diphenyloxazole, 4-ethyloxazole, 4,5-dimethyloxazole, 5-phenyloxazole, etc.), those of the benzoxazole series (e.g., benzoxazole, S-chlorobenzoxazole, S-phenylbenzoxazole, S-methylbenzoxazole, 6-methylbenzoxazole, 5,6-dimethylbenzoxazole, 4,6-dimethylbenzoxazole, S-methoxybenzoxazole, 6-methoxybenzoxazole, S-ethoxybenzoxazole, 6-chlorobenzoxazole, S-hydroxybenzoxazole, 6-hydroxybenzoxazole, etc.), those of the naphthoxazole series (e.g., u-naphthoxazole, ,B-naphthoxazole, etc.), those of the selenazole series (e.g., 4-methylselenazole, 4-phenylselenazole, etc.), those of the benzoselenazole series (e.g., benzoselenazole, 5- chlorobenzoselenazole, S-methoxybenzoselenazole, 5-hydroxybenzoselenazole, tetrahydrobenzoselenazole, etc.), those of the naphthoselenazole series (e.g., u-naphthoselenazole, fl-naphthoselenazole, etc.), those of the thiazoline series '(e.g., thiazoline, 4-methylthiazoline, etc.), those of the 2-quinoline series '(e.g., quinoline, 3-methylquinoline, S-methylquinoline, 7-methylquinoline, 8-methylquinoline, 6-chloroquinoline, =8-chloroquinoline, 6- methoxyquinoline, 6-ethoxyquinoline, 6 hydroxyquinoline, 8 hydroxyquinoline, etc.), those of the 4-quinoline series (e.g., quinoline, 6-methoxyquinoline, 7-methylquinoline, S-methylquinoline, etc.), those of the l-isoquinoline series (e.g., isoquinoline, 3,4-dihydroisoquinoline, etc.), those of the 3,3-dialkylindolenine series (e.g., 3,3-dimethylindolenine, 3,3,5-trimethylindolenine, 3,3,7- trimethylindolenine, etc.), those of the Z-pyridine series (e.g., pyridine, 3-methylpyridine, 4-methylpyridine, 5- methylpyridine, o-methylpyridine, 3,4-dimethylpyridine, 3,5-dimethylpyridlne, 3,6-dimethylpyridine, 4,5-dimethylpyridine, 4,6-dimethylpyridine, 4-phenylpyridine, S-chlo- 4 ropyridine, 6-chloropyridine, 3-hydroxypyridine, 4 hydroxypyridine, 5-hydroxypyridine, 6-hydroxypyridine, 3- phenylpyridine, 4-phenylpyridine, 6-phenlpyridine, etc.), those of the 4-pyridine series (e.g., Z-methylpyridine, 3- methylpyridine, 3-bromopyridine, 3-chloropyridine, 2,3-dimethylpyridine, 2,5-dimethylpyridine, 2,6-dimethylpyridine, Z-hydroxypyridine, 3-hydroxypyridine, etc.), etc.

The class of dyes represented by Formula II are highly useful intermediates for synthesizing dyes containing two cyclic nuclei joined through a straight chain linkage containing at least one methine group, at least one of said nuclei containing N, S, Se, Te or 0. Compounds of Formula II wherein d represents the integer 1 are especially versatile intermediates for synthesizing polymethine dyes. A feature of such intermediates is that the dilactone ring is very easily hydrolyzed to obtain compounds of Formula V I:

wherein -R and Z have the meanings given above, and X" represents an anion such as chloride, bromide, iodide, perchlorate, thiocyanate, benzenesulfonate, p-toluenesulfonate, ethylsulfate, etc. Compounds of Formula VI are known to be highly useful dye intermediates. The

intermediates of Formula VII are more readily prepared by hydrolysis of compounds of Formula M, where d represents :1, than by prior art methods.

Intermediates of Formula 11 wherein d represents 1 are readily prepared by quaternizing a compound having the following formula:

n-1 i -on=cH)..-1=s Any suitable quaternizing agent may be employed such as p-toluene sulfonic acid-esters. The quaternary salt is then reacted with the dilactone ring compound of Formula I to form the intermediate.

Dyes of Formula H wherein d represents 2 can be prepared conveniently, for example, by condensing an intermediate of Formula VI with a dilactone ring compound of Formula I and, for example, ethyl orthoacetate. These dyes are especially useful in preparing the holopolar dyes of Formula H1.

The holopolar dyes of Formula III are excellent spectral sensitizers for photographic silver halide emulsions. This class of dyes may be advantageously prepared, for example by reacting a compound of Formula II wherein d represents 2 with, for example, a compound of the following formula:

wherein R, X and n have the meanings given above.

Dyes of Formula IV are useful filter dyes for photographic elements, and may be prepared, for example, by reacting a compound of Formula I with a suitable alkylene compound such as trimethoxypropene.

The dyes of Formula V are also useful in photographic elements as filter dyes, and are prepared by reacting, for example, a dialkylaminocinnarnaldehyde with a dilactone ring compound of Formula I.

The foregoing methods of synthesizing the present dyes are for the most part condensation reactions, and are accelerated by heating the reaction mixture up to reflux temperatures. Preferably, the reaction is carried out in an inert solvent such as ethanol, n-propanol, n-butanol, pyridine, quinoline, isoquinoline, etc. The reactants can be employed with an excess of one or the other, i.e., greater than the stoichiometrically calculated equivalents, but preferably in an approximately equimolar proportion for the best results. Advantageously, the condensations are carried out in the presence of a basic condens ing agent such as a trialkylamine, e.g., triethylamine, trin-propylamine, tri-n-butylaminc, N-methylpiperidine, N- ethylpiperidine, N,N-dimethylaniline, etc.

This invention will be further illustrated by the following examples. Examples 1 and 2 show the preparation of the novel intermediates of the invention.

EXAMPLE 1 5 3-ethyl-2 3H) -thiazolo [4,5 -b] quinolylidene) 2,2,dimethyl-1,3-dioxane-4,6-dione 3-ethyl-2-methylthiothiazolo [4,5 -b] quinolinium p-toluene-sulfonate (13.0 g., 0.03 mole), 2,2-dimethyl-l,3-dioxane-4,-6-dione (13.0 g., 0.09 mole) and ethyl alcohol (30 ml.) were mixed together in a flask. Triethylamine (5 ml.) was added and the whole was heated at refluxing temperature for 5 minutes and chilled. The solid which began to appear during refluxing was collected by filtration and dried. Yield of crude dye was quantitative. The dye was purified by dissolving it in hot pyridine, filtering the solution and recrystallizing the dye by the addition of methanol to the filtrate. The yield of dye after two such purifications was 6.8 g. (64% M.P. 2 l6-217 (dec.).

EXAMPLE 2 2,2-dimethyl-5 -(3 -phenyl-2(3 H)-thiazolo [4,5 -b] quinolylidene -*l ,3-dioxane-4, 6-dione 2-methylthio-3-phenylthiazolium[4,5 b] quinolinium ptoluenesulfonate (14.7 g., 0.03 mole), 2,2-dimethyl-l,3- dioxane-4,6-dione (16.0 g., 0.09 mole) and ethyl alcohol (30 ml.) were mixed together in a flask. Triethylamine (5 ml.) was added and the whole was heated at refluxing temperature for 5 minutes and chilled. The solid which began to appear during refluxing was collected by filtration and dried. The yield of crude dye was 10.0 g. (83% The dye was purified by dissolving it in hot pyridine, filtering the solution and recrystallizing the dye by the addition of methanol to the filtrate. The yield of dye after two such purifications was 5.5 g. (49%), M.P. above 300.

The ease of hydrolysis of the inter-mediates of the invention, illustrated by those of Examples .1 and 2, to known dye intermediates of Formula V1, is demonstrated in Examples 3 and 4.

EXAMPLE 3 2-methyl-3-phenylthiazolo [4,5 -b] quinolinium chloride C-Me N/ N/ 01 Ph 2,2-dimethyl-5-(3-phenyl-2(3H)-thiazolo [4,5 b]quinolylidene)-1,3-dioxane-2,4-dione (3.68 g., 0.009 mole), hydrochloric acid (200 ml.) (Specific Gravity 1.18) and water ml.) were placed in a flask and refluxed for 3 hours. The solution was concentrated to near dryness, the residue was washed out with acetone and the solid removed by filtration and dried. The yield of crude quaternary salt was quantitative.

6 EXAMPLE 4 3-ethyl-2-methylthiazolo [4,5 -b] quinolinium chloride 5-(3-ethyl-2(3H) thiazolo [4,5-b]quinolylidenc) 2,2- dimethyl-l,3-dioxane-'4,6-dione (3.56 g., 0.01 mole), hydrochloric acid ml.) (Specific Gravity 1.18) and water (15 ml.) were placed in a flask and refluxed for 30 minutes. The solution was then concentrated to near dryness, the residue was washed out with acetone and the solid was removed by filtration and dried. The yield of crude quaternary salt was quantitative.

Preparation of dye intermediates of Formula II wherein d represents at least 2 is illustrated by Examples 5, 6 and 7.

EXAMPLE 5 5- (3-ethyl-2-benzothiazolinylidene l -rnethylethylidene] 2,2-dimethyl-1,3-dioxane-4,6-dione A mixture of 3-ethyl-2-methylbenzothiazolium p-toluene-sulfonate (17.5 g., 1 mole), 2,2-dimethyl-1,3-dioxane- 4,6-dione (7.2 g., 1 mole) and ethyl orthoacetate (16.2 g., 1 mol.+l00%) were heated under reflux in pyridine (50 ml.) for ten minutes. The crude dye was precipitated by the addition of water (200 ml.), the water decanted and the residue boiled with methanol (400 ml.). The dye was collected on a filter and twice recrystallized from pyridine and methanol giving 7.8 g. (46%), M.P. 237-8 (dec.).

EXAMPLE 6 5-[ l-ethylnaphtho[ 1,2-d] thiazolin-2-ylidene)-1 -me'thylethylidene] -2,2-dimethyl-l,3-di0xane-4,6-dione A mixture of 1-ethyl-2-methylnaphtho[1,2-d]thiazolium p-toluenesulfonate (7.98 g., 1 mole), 2,2-dimethyl-1,3- dioxane-4,6-dione (2.88 g., 1 mole) and ethyl orthoacetate (3.24 g., l mol.+300% excess) was heated under reflux in pyridine (20 ml.) solution for ten minutes. The dye crystallized after the addition of methanol (200 ml.) and was collected on a filter. After two recrystallizations from pyridine and methanol, the yield of dye was 2.8 g. (36%), M.P. 264-5 (dec.).

EXAMPLE 7 5-[(1-ethyl-2(1H)-quinolylidene)ethylidene]-2,2-

dimethyl-1,3-dioxane 4,6-dione A mixture of Z-fi-acetanilidovinyl-l-ethylquinolinium iodide (4.5 g., 1 mole) and 2,2-dimethyl-1,3-dioxane-4,6- dione (1.44 g., 1 mole) and triethylamine (1.4 ml., 1 mole) were heated under reflux in ethanol solution (25 ml.) for ten minutes. The crude dye was precipitated by the addition of water (100 ml.), the water decanted and the sticky residue extracted with boiling benzene (200 ml.). After filtering, the benzene was removed under reduced pressure. The residue became crystalline after stirring with methanol and the dye was collected on a filter. After two recrystallizations from methanol, the yield was 1.1 g., M.P. 251-2 (dec.).

Examples 8 and 9 show the synthesis of holopolar sensitizing dyes of Formula III.

EXAMPLE 8 -[bis(3-ethyl-2-benzothiazolinylidene) isopropylidene]- 2,2-dimethyl-1,3-dioxane-4,6-dione A mixture of 3-ethyl-2-ethylmercapto benzothiazolium ethyl sulfate (3.5 g., 1 mol.+100%) and 5-[(3-ethyl-2- benzothiazolinylidene)isopropylidene] 2,2-dimethyl-1,3- dioxane-4,6-dione (1.7 g., 1 mole) and triethylamine (1.4 ml., 1 mol.+100%) in pyridine ml.) were heated under reflux for fifteen minutes. After chilling, the dye was precipitated by the addition of water (100 ml.), the water decanted and the residue boiled with methanol, chilled and solid collected on a filter. After two recrystallizations by dissolving in hot pyridine and filtering into methanol, the yield of dye was 1.5 g. (60%), M.P. 243 4 (dec.).

EXAMPLE 9 5- [bis( l-ethylnaphtho [1,2-d]thiazolin-Z-ylidene)isopropylidene] -2,2-dimethyl-l,3-dioxane-4,6-dione A mixture of 5-[(I-ethylnaphtho[1,2-d]thiazolin-2- ylidene)isopropylidene] 2,2-dimethyl 1,3-dioxane-4,6- dione (1.96 g. 1 mole), 1-ethyl-2-ethylmercaptonaphtho [l,2-d]thiazolium p-toluenesulfonate (4.45 g., 1 mole +100%) and triethylamine (1.4 m1., 1 mol.+100%) in pyridine ml.) was heated under reflux for fifteen minutes. Methanol (200 ml.) was added with stirring and, after chilling, the crude dye was collected on a filter and washed with methanol. After two recrystallizations by dissolving in hot pyridine and filtering into methanol, the yield of dye was 1.5 g. (50% M.P. 20l202 (dec.).

Example 10 illustrates the preparation of an oxonol filter dye of Formula IV.

8 EXAMPLE 10 Bis-[2,2-dimethyl-1,3-dioxane-4,6-dione(5) trimethine oxonol A mixture of 2,2-dimethyl-1,3-dioxane-4,6-dione (2.88 g., 1 mole), trimethoxypropene (2.64 g., 1 |mol.-i-l00%) and triethylamine (2.8 ml., 1 mol.+100%) in pyridine (15 ml.) was heated under reflux for ten minutes. After chilling, the mixture was treated with water 100 ml.) and concentrated hydrochloric acid (10 ml.). The aqueous portion was decanted and the residue stirred with methanol, chilled and the solid collected on a. filter. After two recrystallizations by dissolving in methanol and triethylamine and acidifying with concentrated hydrochloric acid, the yield of dye was 1.8 g. M.P. 187-8 (dec.). The dye had a deep yellow color, with an absorption maximum at 453 mg. The dye is bleachable, and was found to be useful in a hydrophilic colloid layer of a photographic element as a filter for blue radiation.

The preparation of filter dyes of Formula V is shown in Example 11.

EXAMPLE l1 5-p-dimethylaminocinnamylidene-2,2-dimethyl-1,3- dioxane-4,6-dione A mixture of p-dimethylaminocinnamaldehyde (1.75 g., 1 -mol.) and 2,2-dimethyl-1,3-dioxane-4,6-dione (1.44 g., 1 mol.) in ethanol 15 ml.) containing one drop of piperidine was heated under reflux for fifteen minutes. After chilling, the crude dye was collected on a filter, washed with methanol and dried. After two recrystallizations by dissolving in pyridine and filtering into methanol, the yield of dye was 1.5 g. (49%), M.P. 188-9" (dec.) The dye was red in methanol, and had an absorption maximum at 525 m The dye is bleachable, and was found to be useful in a hydrophilic colloid layer in photographic elements as a filter for green radiation.

The sensitizing effect of the dyes of Examples -8 and 9 was tested by adding the dyes to separate portions of a gelatin silver chlorobromide emulsion containing mole percent iodide. The dyes, dissolved in suitable solvents, were added to the separate portions of the emulsion at a concentration of 0.13 grams per mole of silver. After digestion at 50 C. for 10 minutes, the emulsions were coated at 432 mg. of silver per square foot on a cellulose acetate film support. A sample of each coating was exposed on a sensitometer to a wedge spectrograph, processed for 3 minutes in Kodak Developer D-19, fixed, washed and dried. The dye of Example 8 had a sensitizing range of 520 to 630 m with a sensitizing maximum at 600 III/1..

The dye of Example 9 sensitized in the range of 530 to 680 mg, with maximum sensitization at 640 my.

In the preparation of photographic emulsions, the new dyes of the invention are advantageously incorporated in the washed, finished silver halide emulsion and should, of course, be uniformly distributed throughout the emulsion. The methods of incorporating dyes in emulsions are relatively simple and well known to those skilled in the art of emulsion making. For example, it is convenient to add the dyes from solutions in appropriate solvents, in which case the solvent selected should be completely free from any deleterious cheat on the ultimate light-sensitive materials. Methanol, isopropanol, pyridine, etc., alone or in admixtures, have proven satisfactory as solvents for the majority of our new dyes. The type of silver halide emulsions that can be sensitized with the new dyes include any of those prepared with hydrophilic colloids that are known to be satisfactory for dispersing silver halides, for example, emulsions comprising natural materials such as gelatin, albumin, agar-agar, gum arabic, alginic acid, etc., and hydrophilic synthetic resins such as polyvinyl alcohol, polyvinyl pyrrolidone, cellulose ethers, partially hydrolyzed cellulose acetate, and the like.

The concentration of the new dyes in the emulsion can vary widely, i.e., from about to about 100 mgs. .per liter of flowable emulsion. The specific concentration will vary according to the type of light-sensitive material in the emulsion and according to the effects desired. The suitable and most economical concentration for any given emulsion will be apparent to those skilled in the art upon making the tests and observations customarily used in the art of emulsion making.

To prepare a gelatino-silver halide emulsion sensitized with one of the new dyes, the following procedure is satisfactory: A quantity of the dye is dissolved in a suitable solvent and a volume of this solution containing from 5 to 100 mgs. of dye is slowly added to about 1000 cc. of a gelatino-silver halide emulsion. With most of the dyes, to mgs. of dye per liter of emulsion suffice to produce the maximum sensitizing effect with the ordinary gelatino-silver bromide (including bromoiodide and chlorobromide) emulsions. With fine-grain emulsions, which include most of the ordinary employed gelatino-silver chloride emulsions, somewhat larger concentrations of dye may be necessary to secure optimum sensitizing effect. While the preceding has dealt with emulsions comprising gelatin, it will be understood that these remarks apply generally to any emulsions wherein part or all of the gelatin is substituted by another suitable hydrophilic colloid such as mentioned above.

The above statements are only illustrative and are not to be understood as limiting the invention in any sense, as it will be apparent that the new dyes can be incorporated by other methods in many of the photographic silver halide emulsions customarily employed in the art. For instance, the dyes can be incorporated by bathing a plate or film upon which an emulsion has been coated, in the solution of the dye in an appropriate solvent. Bathing methods, however, are not to be preferred ordinarily.

Photographic silver halide emulsions, such as those listed above, containing the sensitizing dyes of the invention can also contain such addenda as chemical sensitizers, e.g., sulfur sensitizers (e.g., allyl thiocarba-mide, thiourea allylisothiocyanate, cystine, etc.), various gold compounds (e.g., potassium chloroaurate, auric trichloride, etc.) (see U.S. patents to W. D. Baldsiefen, 2,540,085, granted Feb. 6, 1951; R. E. Damschroder, 2,597,856, granted May 27, 1952; and H. C. Yutzy et al., 2,597,915, granted May 27, 1952); various palladium compounds, such as palladium chloride (W. D. Baldsiefen, U.S. 2,540,086, granted Feb. 6, 1951); potassium chloropall-adate (R. E. S-tauffer et al., U.S. 2,598,079, granted May 27, 1952), etc., or mixture of such sensitizers; antifoggants, such as ammonium chloroplatinate (A. P. H. Trivelli et al., U.S. 2,566,245, granted Aug. 28, 1951); ammonium chloroplatinite (A. P. H. Trivelli et al., U.S. 2,566,263, granted Aug. 28, 1951); benzotriazole, nitrobenzimidazole, S-nitroindazole, benzidine, mere-aptans, etc. (see Mees, The Theory of the Photographic Process, MacMillan Pub., 1942, page 460), or mixtures thereof; hardeners, such as formaldehyde (A. Miller, U.S. 1,763,533, granted June 10, 1930); chrome alum (U.S. 1,763,533); glyoxal (J. Brunken, U.S. 1,870,354, granted Aug. 9, 1932); dibromacrolein (0. Block et al., British 406,750, accepted Mar. 8, 1934), etc.; color couplers, such as those described in I. F. Salminen et al., U.S. Patent 2,423,730, granted July 7, 1947; Spence and Carroll, U.S. Patent 2,640,776, issued June 2, 1953, etc.; or mixtures of such addenda. Dispersing agents for color couplers, such as those set forth in U.S. patents to E. E. Jelley et al., 2,322,027, granted June 15, 1943, and L. D. Maunes et al., 2,304,940, granted Dec. 15, 1942, can also be employed in the above-described emulsions.

Although the photographic element example shows coatings made on cellulose acetate supports, it is to be understood that the photographic silver halide emulsions are coated advantageously on any of the support materials used in photographic elements, including glass, paper, polyolefin coated paper, cellulose acetate, cellulose nitrate, and synthetic film-forming resinous materials, such as, the polystyrenes, the polyesters, the polyarnides, etc.

The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected with the spirit and scope of the invention as described hereinabove and as defined in the appended claims.

I claim:

1. A photographic silver halide emulsion containing a sensitizing quantity of a dye having the following formu a:

wherein R and R" each represents a substituent selected from the group consisting of a hydrocarbon alkyl substituent of from 1 to 12 carbon atoms and cycloalkyl nuclei containing from 4 to 6 carbon atoms; x, m and n each represents an integer of from 1 to 2; R and R each represents a substituent selected from the group consisting of a hydrocarbon alkyl substituent of from 1 to 12 carbon atoms and an aryl nucleus; Z and Z each represents the nonmetallic atoms necessary to complete a hetenocyclic nucleus of 5 to 6 carbon atoms, n represents an integer of from 1 to 2; and, R and R each represents a substituent selected from the group consisting of hydrogen, a methyl group, an ethyl group and a phenyl nucleus.

2. A photographic silver halide emulsion sensitized with a dye represented by the following formula:

1 1 1 2 3. A photographic silver halide emulsion sensitized with References Cited a dye represented by the following formula: UNITED STATES PATENTS 2,739,964 3/1956 Brooker et a1. 96105 0 3,140,182 7/1964 Haseltlne 96106 s S 3,140,951 7/1964 Haseltine 96101 OTHER REFERENCES C=CHC=CH-C Kensdall, I-IX Congres International Photographlque,

t; 10 pp. 227, 235 and 252 (1935). M 3 Et J. TRAVIS BROWN, Primary Examiner.

c US. 01. X.R. 

